3. Control Flow Statements

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3. Control Flow Statements

May 24, 2026 in Python

Control flow statements control the execution of a program based on conditions and loops.

Decision Making Statements

1. if Statement

The if statement executes code only if the condition is True.

Syntax

if condition:
    # code

Example

age = 18

if age >= 18:
    print("You can vote")

Output:

You can vote

2. if...else Statement

Used when there are two possible outcomes.

Syntax

if condition:
    # code if true
else:
    # code if false

Example

number = 5

if number % 2 == 0:
    print("Even")
else:
    print("Odd")

3. if...elif...else Statement

Used to check multiple conditions.

Syntax

if condition1:
    # code
elif condition2:
    # code
else:
    # code

Example

marks = 75

if marks >= 90:
    print("Grade A")
elif marks >= 60:
    print("Grade B")
else:
    print("Grade C")

Nested Conditions

An if statement inside another if statement is called nested condition.

Example

age = 25
citizen = True

if age >= 18:
    if citizen:
        print("Eligible to vote")

Loops in Python

Loops are used to repeat code multiple times.

Python has:

  • for loop
  • while loop

1. for Loop

Used to iterate over a sequence.

Syntax

for variable in sequence:
    # code

Example 1: Loop through List

fruits = ["Apple", "Banana", "Mango"]

for fruit in fruits:
    print(fruit)

Example 2: Loop through String

for ch in "Python":
    print(ch)

2. while Loop

Runs as long as condition is True.

Syntax

while condition:
    # code

Example

count = 1

while count <= 5:
    print(count)
    count += 1

Infinite Loop

If condition never becomes false.

while True:
    print("Running forever")

Use carefully.

Loop Control Statements

Used to control loop execution.

1. break

Stops the loop immediately.

Example

for i in range(1, 10):
    if i == 5:
        break
    print(i)

Output:

1
2
3
4

2. continue

Skips current iteration and moves to next iteration.

Example

for i in range(1, 6):
    if i == 3:
        continue
    print(i)

Output:

1
2
4
5

3. pass

Does nothing.

Used as placeholder.

Example

for i in range(5):
    pass
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Range Function

The range() function generates a sequence of numbers.

Syntax

range(start, stop, step)

Parameters:

  • start → starting value
  • stop → ending value (excluded)
  • step → increment/decrement

Example 1: Basic Range

for i in range(5):
    print(i)

Output:

0
1
2
3
4

Example 2: Start and Stop

for i in range(2, 6):
    print(i)

Output:

2
3
4
5

Example 3: Step Value

for i in range(1, 10, 2):
    print(i)

Output:

1
3
5
7
9

Reverse Loop

for i in range(10, 0, -1):
    print(i)

Nested Loops

Loop inside another loop.

Example

for i in range(1, 4):
    for j in range(1, 3):
        print(i, j)

Practical Examples

Example 1: Sum of Numbers

total = 0

for i in range(1, 6):
    total += i

print(total)

Output:

15

Example 2: Multiplication Table

num = 5

for i in range(1, 11):
    print(num, "x", i, "=", num * i)

aditya singh